If any provision of this subchapter or the application thereof to any person or circumstances is held invalid, the remainder of the subchapter and the application of the provision to other persons not similarly situated or to other circumstances shall not be affected thereby. ( Pub. L. 90–284, title VIII, § 820 , formerly § 819, Apr. 11, 1968 , 82 Stat. 89 ; renumbered § 820, Pub. L. 100–430, § 8(1) , Sept. 13, 1988 , 102 Stat. 1625 .) CFR Title Parts 10 1040 12 27 , 390 , 626 23 200 24 81 , 91 , 103 , 105 , 109 , 111 , 115 , 180 32 192